The nucleus of the corporation is the C. Bertelsmann Verlag, a publishing house established in 1835 by Carl Bertelsmann in Gütersloh. Carl Bertelsmann was a representative of the "Minden-Ravensberger Erweckungsbewegung", a Protestant revival movement, whose writings he published. The C. Bertelsmann Verlag, originally specialized in theological literature, expanded its publications to include school and textbooks, and in the 1920s and 1930s increasingly entered into the field of light fiction. During the Third Reich, the publishing house gained a prominent position with its affordable "Bertelsmann Volksausgaben" ("people's editions"). In particular, war adventure books such as Werner von Langsdorff's "Fliegerbuch" on aviation were a commercial success. Heinrich Mohn belonged to the patrons' circle of the paramilitary Schutzstaffel organization and sought to turn his company into a National Socialist model enterprise. During World War II, the C. Bertelsmann Verlag became a leading supplier to the Wehrmacht, even surpassing the central publishing house of the NSDAP Franz Eher. Especially in the years between 1939 and 1941, the revenues of the C. Bertelsmann Verlag skyrocketed. Jewish slave laborers were not forced to work in Gütersloh, but in printing plants in Lithuania with which the C. Bertelsmann Verlag cooperated. In 1944, the Reichsschrifttumskammer (Reich Chamber of Literature) closed the publishing house to "mobilize all powers for victory". Another essential reason for this was criminal paper racketeering by some publisher's employees, which led to a trial in 1944.